1. Field of the Invention
Described in U.S. Pat. No. 5,290,544 are water-soluble glasses for application in cosmetic products with very small SiO2 and very high B2O3 or high P2O5 contents. The glasses have silver concentrations of <0.5 wt %. These glasses have an extremely low hydrolytic resistance and have the drawback of completely dissolving in water. The antibacterial action in these glasses is effected by the liberated Ag and/or Cu ions.
2. Background of the Invention
Described in U.S. Pat. No. 6,143,318 are silver-containing phosphate glasses, which, as antimicrobial material for the treatment of wound infection, use combinations of Cu, Ag, and Zn. The drawback of these glasses is their low hydrolytic resistance, which is expressed in the fact that the glasses are completely water-soluble. These glasses contain no Al2O3 and/or SiO2, which serve to adjust the hydrolytic resistance. Furthermore, the concentration of Na2O of 34 mol % is very high. This is responsible for the fact that the reactivity of the glass is very high and that it dissolves completely relatively rapidly.
Phosphate or borophosphate glasses that have no titanium have also become known from the following documents:
JP A 2001 247,333
JP A 2001 247,335
JP A 2001 247,336
JP A 2001 247,337
JP A 92 338,129
JP A 2001 247,333 describes a glass fiber that is furnished antimicrobially with Ag2O in a later process step.
JP A 2001 247,336, JP A 2001 247,335 also describe a glass composition that is furnished antimicrobially with Ag2O in a subsequent process step.
The subsequent addition of Ag2O leads to the fact that composite materials are formed, in which silver or silver agglomerates are deposited on the surface of the glass phase, so that a homogeneous distribution of the silver is not present.
Described in JP 92 338,129 is a soluble glass that may be free of alkalis and aluminum is described. This glass achieves its antimicrobial action through the addition of silver.
Glass compositions that contain TiO2 are known from the following documents:
JP A 2002 012,442
JP A 96 048,539
EP A 141,580
JP A 2000 327,369
The glasses known from the documents EP A 141,580 and JP A 2000 327,369 have a phosphorus content that is less than 45 wt %.
The glasses known from the documents JP A 2002 012,442 and JP A 96 048,539 have an alkali content that is greater than 0.39 wt %, which, for use in polymers, such as, for example, polycarbonate, has the drawback that such alkali concentrations can lead to chain rupture and thus the polymer degenerates. In addition, as a rule, there arises an undesired discoloration of the polymers.